/*
 * WPA Supplicant / wrapper functions for libcrypto
 * Copyright (c) 2004-2009, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"
#include <openssl/opensslv.h>
#include <openssl/err.h>
#include <openssl/des.h>
#include <openssl/aes.h>
#include <openssl/bn.h>
#include <openssl/evp.h>
#include <openssl/dh.h>

#include "common.h"
#include "wpabuf.h"
#include "dh_group5.h"
#include "crypto.h"

#if OPENSSL_VERSION_NUMBER < 0x00907000
#define DES_key_schedule des_key_schedule
#define DES_cblock des_cblock
#define DES_set_key(key, schedule) des_set_key((key), *(schedule))
#define DES_ecb_encrypt(input, output, ks, enc) \
    des_ecb_encrypt((input), (output), *(ks), (enc))
#endif /* openssl < 0.9.7 */

static BIGNUM * get_group5_prime(void)
{
#if OPENSSL_VERSION_NUMBER < 0x00908000
    static const unsigned char RFC3526_PRIME_1536[] = {
        0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xC9,0x0F,0xDA,0xA2,
        0x21,0x68,0xC2,0x34,0xC4,0xC6,0x62,0x8B,0x80,0xDC,0x1C,0xD1,
        0x29,0x02,0x4E,0x08,0x8A,0x67,0xCC,0x74,0x02,0x0B,0xBE,0xA6,
        0x3B,0x13,0x9B,0x22,0x51,0x4A,0x08,0x79,0x8E,0x34,0x04,0xDD,
        0xEF,0x95,0x19,0xB3,0xCD,0x3A,0x43,0x1B,0x30,0x2B,0x0A,0x6D,
        0xF2,0x5F,0x14,0x37,0x4F,0xE1,0x35,0x6D,0x6D,0x51,0xC2,0x45,
        0xE4,0x85,0xB5,0x76,0x62,0x5E,0x7E,0xC6,0xF4,0x4C,0x42,0xE9,
        0xA6,0x37,0xED,0x6B,0x0B,0xFF,0x5C,0xB6,0xF4,0x06,0xB7,0xED,
        0xEE,0x38,0x6B,0xFB,0x5A,0x89,0x9F,0xA5,0xAE,0x9F,0x24,0x11,
        0x7C,0x4B,0x1F,0xE6,0x49,0x28,0x66,0x51,0xEC,0xE4,0x5B,0x3D,
        0xC2,0x00,0x7C,0xB8,0xA1,0x63,0xBF,0x05,0x98,0xDA,0x48,0x36,
        0x1C,0x55,0xD3,0x9A,0x69,0x16,0x3F,0xA8,0xFD,0x24,0xCF,0x5F,
        0x83,0x65,0x5D,0x23,0xDC,0xA3,0xAD,0x96,0x1C,0x62,0xF3,0x56,
        0x20,0x85,0x52,0xBB,0x9E,0xD5,0x29,0x07,0x70,0x96,0x96,0x6D,
        0x67,0x0C,0x35,0x4E,0x4A,0xBC,0x98,0x04,0xF1,0x74,0x6C,0x08,
        0xCA,0x23,0x73,0x27,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
    };
    return BN_bin2bn(RFC3526_PRIME_1536, sizeof(RFC3526_PRIME_1536), NULL);
#else /* openssl < 0.9.8 */
    return get_rfc3526_prime_1536(NULL);
#endif /* openssl < 0.9.8 */
}

#if OPENSSL_VERSION_NUMBER < 0x00908000
#ifndef OPENSSL_NO_SHA256
#ifndef OPENSSL_FIPS
#define NO_SHA256_WRAPPER
#endif
#endif

#endif /* openssl < 0.9.8 */

#ifdef OPENSSL_NO_SHA256
#define NO_SHA256_WRAPPER
#endif

static int openssl_digest_vector(const EVP_MD *type, int non_fips,
        size_t num_elem, const u8 *addr[],
        const size_t *len, u8 *mac)
{
    EVP_MD_CTX ctx;
    size_t i;
    unsigned int mac_len;

    EVP_MD_CTX_init(&ctx);
#ifdef CONFIG_FIPS
#ifdef OPENSSL_FIPS
    if (non_fips)
        EVP_MD_CTX_set_flags(&ctx, EVP_MD_CTX_FLAG_NON_FIPS_ALLOW);
#endif /* OPENSSL_FIPS */
#endif /* CONFIG_FIPS */
    if (!EVP_DigestInit_ex(&ctx, type, NULL)) {
        wpa_printf(MSG_ERROR, "OpenSSL: EVP_DigestInit_ex failed: %s",
                ERR_error_string(ERR_get_error(), NULL));
        return -1;
    }
    for (i = 0; i < num_elem; i++) {
        if (!EVP_DigestUpdate(&ctx, addr[i], len[i])) {
            wpa_printf(MSG_ERROR, "OpenSSL: EVP_DigestUpdate "
                    "failed: %s",
                    ERR_error_string(ERR_get_error(), NULL));
            return -1;
        }
    }
    if (!EVP_DigestFinal(&ctx, mac, &mac_len)) {
        wpa_printf(MSG_ERROR, "OpenSSL: EVP_DigestFinal failed: %s",
                ERR_error_string(ERR_get_error(), NULL));
        return -1;
    }

    return 0;
}


int md4_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
    return openssl_digest_vector(EVP_md4(), 0, num_elem, addr, len, mac);
}


void des_encrypt(const u8 *clear, const u8 *key, u8 *cypher)
{
    u8 pkey[8], next, tmp;
    int i;
    DES_key_schedule ks;

    /* Add parity bits to the key */
    next = 0;
    for (i = 0; i < 7; i++) {
        tmp = key[i];
        pkey[i] = (tmp >> i) | next | 1;
        next = tmp << (7 - i);
    }
    pkey[i] = next | 1;

    DES_set_key(&pkey, &ks);
    DES_ecb_encrypt((DES_cblock *) clear, (DES_cblock *) cypher, &ks,
            DES_ENCRYPT);
}


int rc4_skip(const u8 *key, size_t keylen, size_t skip,
        u8 *data, size_t data_len)
{
#ifdef OPENSSL_NO_RC4
    return -1;
#else /* OPENSSL_NO_RC4 */
    EVP_CIPHER_CTX ctx;
    int outl;
    int res = -1;
    unsigned char skip_buf[16];

    EVP_CIPHER_CTX_init(&ctx);
    if (!EVP_CIPHER_CTX_set_padding(&ctx, 0) ||
            !EVP_CipherInit_ex(&ctx, EVP_rc4(), NULL, NULL, NULL, 1) ||
            !EVP_CIPHER_CTX_set_key_length(&ctx, keylen) ||
            !EVP_CipherInit_ex(&ctx, NULL, NULL, key, NULL, 1))
        goto out;

    while (skip >= sizeof(skip_buf)) {
        size_t len = skip;
        if (len > sizeof(skip_buf))
            len = sizeof(skip_buf);
        if (!EVP_CipherUpdate(&ctx, skip_buf, &outl, skip_buf, len))
            goto out;
        skip -= len;
    }

    if (EVP_CipherUpdate(&ctx, data, &outl, data, data_len))
        res = 0;

out:
    EVP_CIPHER_CTX_cleanup(&ctx);
    return res;
#endif /* OPENSSL_NO_RC4 */
}


int md5_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
    return openssl_digest_vector(EVP_md5(), 0, num_elem, addr, len, mac);
}


#ifdef CONFIG_FIPS
int md5_vector_non_fips_allow(size_t num_elem, const u8 *addr[],
        const size_t *len, u8 *mac)
{
    return openssl_digest_vector(EVP_md5(), 1, num_elem, addr, len, mac);
}
#endif /* CONFIG_FIPS */


int sha1_vector(size_t num_elem, const u8 *addr[], const size_t *len, u8 *mac)
{
    return openssl_digest_vector(EVP_sha1(), 0, num_elem, addr, len, mac);
}


#ifndef NO_SHA256_WRAPPER
int sha256_vector(size_t num_elem, const u8 *addr[], const size_t *len,
        u8 *mac)
{
    return openssl_digest_vector(EVP_sha256(), 0, num_elem, addr, len,
            mac);
}
#endif /* NO_SHA256_WRAPPER */


void * aes_encrypt_init(const u8 *key, size_t len)
{
    AES_KEY *ak;
    ak = os_malloc(sizeof(*ak));
    if (ak == NULL)
        return NULL;
    if (AES_set_encrypt_key(key, 8 * len, ak) < 0) {
        os_free(ak);
        return NULL;
    }
    return ak;
}


void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
{
    AES_encrypt(plain, crypt, ctx);
}


void aes_encrypt_deinit(void *ctx)
{
    os_free(ctx);
}


void * aes_decrypt_init(const u8 *key, size_t len)
{
    AES_KEY *ak;
    ak = os_malloc(sizeof(*ak));
    if (ak == NULL)
        return NULL;
    if (AES_set_decrypt_key(key, 8 * len, ak) < 0) {
        os_free(ak);
        return NULL;
    }
    return ak;
}


void aes_decrypt(void *ctx, const u8 *crypt, u8 *plain)
{
    AES_decrypt(crypt, plain, ctx);
}


void aes_decrypt_deinit(void *ctx)
{
    os_free(ctx);
}


int crypto_mod_exp(const u8 *base, size_t base_len,
        const u8 *power, size_t power_len,
        const u8 *modulus, size_t modulus_len,
        u8 *result, size_t *result_len)
{
    BIGNUM *bn_base, *bn_exp, *bn_modulus, *bn_result;
    int ret = -1;
    BN_CTX *ctx;

    ctx = BN_CTX_new();
    if (ctx == NULL)
        return -1;

    bn_base = BN_bin2bn(base, base_len, NULL);
    bn_exp = BN_bin2bn(power, power_len, NULL);
    bn_modulus = BN_bin2bn(modulus, modulus_len, NULL);
    bn_result = BN_new();

    if (bn_base == NULL || bn_exp == NULL || bn_modulus == NULL ||
            bn_result == NULL)
        goto error;

    if (BN_mod_exp(bn_result, bn_base, bn_exp, bn_modulus, ctx) != 1)
        goto error;

    *result_len = BN_bn2bin(bn_result, result);
    ret = 0;

error:
    BN_free(bn_base);
    BN_free(bn_exp);
    BN_free(bn_modulus);
    BN_free(bn_result);
    BN_CTX_free(ctx);
    return ret;
}


struct crypto_cipher {
    EVP_CIPHER_CTX enc;
    EVP_CIPHER_CTX dec;
};


struct crypto_cipher * crypto_cipher_init(enum crypto_cipher_alg alg,
        const u8 *iv, const u8 *key,
        size_t key_len)
{
    struct crypto_cipher *ctx;
    const EVP_CIPHER *cipher;

    ctx = os_zalloc(sizeof(*ctx));
    if (ctx == NULL)
        return NULL;

    switch (alg) {
#ifndef OPENSSL_NO_RC4
        case CRYPTO_CIPHER_ALG_RC4:
            cipher = EVP_rc4();
            break;
#endif /* OPENSSL_NO_RC4 */
#ifndef OPENSSL_NO_AES
        case CRYPTO_CIPHER_ALG_AES:
            switch (key_len) {
                case 16:
                    cipher = EVP_aes_128_cbc();
                    break;
                case 24:
                    cipher = EVP_aes_192_cbc();
                    break;
                case 32:
                    cipher = EVP_aes_256_cbc();
                    break;
                default:
                    os_free(ctx);
                    return NULL;
            }
            break;
#endif /* OPENSSL_NO_AES */
#ifndef OPENSSL_NO_DES
        case CRYPTO_CIPHER_ALG_3DES:
            cipher = EVP_des_ede3_cbc();
            break;
        case CRYPTO_CIPHER_ALG_DES:
            cipher = EVP_des_cbc();
            break;
#endif /* OPENSSL_NO_DES */
#ifndef OPENSSL_NO_RC2
        case CRYPTO_CIPHER_ALG_RC2:
            cipher = EVP_rc2_ecb();
            break;
#endif /* OPENSSL_NO_RC2 */
        default:
            os_free(ctx);
            return NULL;
    }

    EVP_CIPHER_CTX_init(&ctx->enc);
    EVP_CIPHER_CTX_set_padding(&ctx->enc, 0);
    if (!EVP_EncryptInit_ex(&ctx->enc, cipher, NULL, NULL, NULL) ||
            !EVP_CIPHER_CTX_set_key_length(&ctx->enc, key_len) ||
            !EVP_EncryptInit_ex(&ctx->enc, NULL, NULL, key, iv)) {
        EVP_CIPHER_CTX_cleanup(&ctx->enc);
        os_free(ctx);
        return NULL;
    }

    EVP_CIPHER_CTX_init(&ctx->dec);
    EVP_CIPHER_CTX_set_padding(&ctx->dec, 0);
    if (!EVP_DecryptInit_ex(&ctx->dec, cipher, NULL, NULL, NULL) ||
            !EVP_CIPHER_CTX_set_key_length(&ctx->dec, key_len) ||
            !EVP_DecryptInit_ex(&ctx->dec, NULL, NULL, key, iv)) {
        EVP_CIPHER_CTX_cleanup(&ctx->enc);
        EVP_CIPHER_CTX_cleanup(&ctx->dec);
        os_free(ctx);
        return NULL;
    }

    return ctx;
}


int crypto_cipher_encrypt(struct crypto_cipher *ctx, const u8 *plain,
        u8 *crypt, size_t len)
{
    int outl;
    if (!EVP_EncryptUpdate(&ctx->enc, crypt, &outl, plain, len))
        return -1;
    return 0;
}


int crypto_cipher_decrypt(struct crypto_cipher *ctx, const u8 *crypt,
        u8 *plain, size_t len)
{
    int outl;
    outl = len;
    if (!EVP_DecryptUpdate(&ctx->dec, plain, &outl, crypt, len))
        return -1;
    return 0;
}


void crypto_cipher_deinit(struct crypto_cipher *ctx)
{
    EVP_CIPHER_CTX_cleanup(&ctx->enc);
    EVP_CIPHER_CTX_cleanup(&ctx->dec);
    os_free(ctx);
}


void * dh5_init(struct wpabuf **priv, struct wpabuf **publ)
{
    DH *dh;
    struct wpabuf *pubkey = NULL, *privkey = NULL;
    size_t publen, privlen;

    *priv = NULL;
    *publ = NULL;

    dh = DH_new();
    if (dh == NULL)
        return NULL;

    dh->g = BN_new();
    if (dh->g == NULL || BN_set_word(dh->g, 2) != 1)
        goto err;

    dh->p = get_group5_prime();
    if (dh->p == NULL)
        goto err;

    if (DH_generate_key(dh) != 1)
        goto err;

    publen = BN_num_bytes(dh->pub_key);
    pubkey = wpabuf_alloc(publen);
    if (pubkey == NULL)
        goto err;
    privlen = BN_num_bytes(dh->priv_key);
    privkey = wpabuf_alloc(privlen);
    if (privkey == NULL)
        goto err;

    BN_bn2bin(dh->pub_key, wpabuf_put(pubkey, publen));
    BN_bn2bin(dh->priv_key, wpabuf_put(privkey, privlen));

    *priv = privkey;
    *publ = pubkey;
    return dh;

err:
    wpabuf_free(pubkey);
    wpabuf_free(privkey);
    DH_free(dh);
    return NULL;
}


struct wpabuf * dh5_derive_shared(void *ctx, const struct wpabuf *peer_public,
        const struct wpabuf *own_private)
{
    BIGNUM *pub_key;
    struct wpabuf *res = NULL;
    size_t rlen;
    DH *dh = ctx;
    int keylen;

    if (ctx == NULL)
        return NULL;

    pub_key = BN_bin2bn(wpabuf_head(peer_public), wpabuf_len(peer_public),
            NULL);
    if (pub_key == NULL)
        return NULL;

    rlen = DH_size(dh);
    res = wpabuf_alloc(rlen);
    if (res == NULL)
        goto err;

    keylen = DH_compute_key(wpabuf_mhead(res), pub_key, dh);
    if (keylen < 0)
        goto err;
    wpabuf_put(res, keylen);
    BN_free(pub_key);

    return res;

err:
    BN_free(pub_key);
    wpabuf_free(res);
    return NULL;
}


void dh5_free(void *ctx)
{
    DH *dh;
    if (ctx == NULL)
        return;
    dh = ctx;
    DH_free(dh);
}
